The invention relates generally to radar systems, and more particularly, to radar range measurement.
Typically, a radar system (or more simply a radar) tracks a target's centroid position to obtain an estimate of ballistic flight characteristics for range determination. To obtain estimates of ballistic flight, radar systems typically use filters such as Kalman filters of relatively high order to produce range measurement data. Such filtering is designed to model only a target's ballistic trajectory. Therefore, it is possible to track and measure range from target trajectory quite accurately.
To observe small variations in range due to motions other than ballistic motion, it is necessary to sample target returns in a manner that ensures that phase change measured from one radar pulse to the next is unambiguous. Such unambiguous phase measurements require a significant amount of radar system resources, more specifically, higher signal-to-noise (SNR) and data rates, thus reducing the safety margin built into the radar to cope with interferers such as main beam jamming or an increased number of targets.